The present invention relates to a CPU heat sink mounting structure, and more specifically to a heat sink fastener used in a CPU heat sink mounting structure to secure a heat sink and a CPU holder firmly together.
FIGS. 1 and 2 show two CPU heat sink mounting structures according to the prior art, in which a curved steel wire rod 13 or substantially U-shaped clamping plate 14 is fastened to two retainer blocks 121' of a CPU holder 12' to hold down a heat sink 11, which carries a fan 10, permitting the heat sink 11 to be firmly retained in close contact with a CPU 20' in the CPU holder 12'. Because the curved steel wire rod 13 or U-shaped clamping plate 14 is simply bridged over the heat sink 11 to impart it with a downward pressure, the heat sink 11 tends to be forced by an external force to displace on the CPU 20' above the CPU holder 12'. Furthermore, the spring power of the curved steel wire rod 13 or U-shaped clamping plate 14 gradually reduces with use, causing it unable to firmly retain the heat sink 11 in place.